Recipe for rebuild for more mid range

[m in sc]

its hard to know till you do. I'll be honest, they are fine. if you want midrange.. these really aren't the ideal bikes for that. the closer to stock the better for that, including pipes..... piston port models are great mid range. BUT, you -can- get decent midrange out of a stock ported/stock head setup.

heres my 72 R5 with an rd motor in it. ebay cyls, FP (vintage) chambers, cdi and programmable box with cheap flat-slide with a y boot & k&n & some v force reeds. its quite useable from 3k-on, and this is primarily due to the ign curve and not going too big on carbs. not sure about HP numbers, really dont care, but it gets to 100 quick and has good manners around town

watch the tach.

[Jung]

Totally agree, with m in sc. Without powervalves, best you'll get is about 3k rpm of usable power and some overrev. Where you want it, depends on the ports and pipes. It's difficult to shift the hit much below 5.5k though, because the stock port timing is already pretty racy.

 FWIW, I suspect that dyno is not a like for like comparison under 4k, good chance he's only opened the taps at 4.5k or so. Mine is nice and tractable from about 4k, but it's not going anywhere fast until just under 6.

I grew up roadracing 125s so 6-9k IS midrange for me!

That R5 sounds sweet!

[RDDave]

its hard to know till you do. I'll be honest, they are fine. if you want midrange.. these really aren't the ideal bikes for that. the closer to stock the better for that, including pipes..... piston port models are great mid range. BUT, you -can- get decent midrange out of a stock ported/stock head setup.

heres my 72 R5 with an rd motor in it. ebay cyls, FP (vintage) chambers, cdi and programmable box with cheap flat-slide with a y boot & k&n & some v force reeds. its quite useable from 3k-on, and this is primarily due to the ign curve and not going too big on carbs. not sure about HP numbers, really dont care, but it gets to 100 quick and has good manners around town

watch the tach.

[m in sc]

the point of me posting that was to show even w stock porting and heads, they -can- be quite useable down low while retaining good high rpm power. IMHO thats about as good as it gets w out cutting heads. I have heard of quite a few people actually going down to 26mm carbs, which isnt a bad idea (as counterintuitive as that may be). but keep in mind, the LC/RZ and Banshee came stock with 26mm carbs.

[RDDave]

Your bike pulls clean and pulls hard. I would be very happy with that combo. I have cleaned up the Bassanis and am repacking them now. Should have them on today and do a test ride.

I am fairly committed to the head mods. And am considering new carbs since they are not a ton of money and you have provided enough information to get it real close to start.

My bike starts and runs good, but compression is down at 95lbs. I plan to pull it down this winter and see if rings will do it or if it needs more. It doesn't rattle and with only 5,000 miles, a simple re-ring is possible.

The recipes and tips that you guys have successfully used and are sharing is way cool. Keeps us novices from eating up bunches of parts and time.

Thank you very much!

[John Ritter]

I use multiple engine/porting programs daily. I started in 1993 with SAE's attempt to rewrite Blairs into dos then Tom Turner made them his TSR's programs and I got them as soon as they were marketed (maybe 1995 or 6 or 7, don't remember) then got Mota, never liked it, then numerous others. I still use all of them except Mota because each one has something to offer. In early 2007 I leased ENGMOD2. This program is the best I'm aware of but the damn thing will drive you out of your friggin mind playing "what if", it is not for the beginner and most new users give up, start with a couple programs that are not as good but will get you exposed, yes they may have faults but will teach you some basics until you're ready to advance.

[racerclam]

Venturi dividers will provide better roll on performance stronger all Throttle openings including mid-range less light switch

[racerclam]

MY pictures did not load .????

[racerclam]

IM not having any luck loading pictures from my phone or computer , If anyone wants  to see pictures of the carbs text me and I can send that way. 702-858-9177

[m in sc]

the pics are there.    they loaded.

as said, un-ported un modified internals leave a lot of meat on the bone, i pretty much wanted to do that bike with strictly bolts ons, just because.

[RDDave]

Did a short test with the Bassani pipes this afternoon. Didn't have the baffles packed and in yet, but I just had to try a short run. WOW! Quite the difference. Much less burbling around 5k, pulls harder and longer. Probably picked up 500RPM. It seems to want to be shifted about 9k now.

Can't wait to get the baffles packed and in so that I can play/test some more.

Didn't seem to help the mid range, but it really picked up up top.